A refrigerated fixture has a product support positioned over a recessed area, referred to as a “case tank”. An air curtain is used to maintain product positioned on the product support within a required temperature range, often referred to as a “core temperature” or “critical air temperature”. The air curtain keeps out ambient air that would raise the product temperature and has little or no discharge of cool air into the room.
The air curtain has a circular circulation of air. Cool air exiting a refrigeration unit is discharged onto a first side of the product support and flows across the product to a second side of the product support. A return air duct is positioned at the second side of the product support and a fan is positioned within the case tank. The fan draws air through the return air duct and directs the air back into the refrigeration unit.
With some types of product, such as fruit and vegetables, water misters operated on timers are used to moisten the product. With other types of product, such as seafood and red meat, the product has natural juices that drip through the product support and into the case tank. As a result, the case tank tends to be a cool, damp and dark environment. Unfortunately many bacteria, such as Pseudomonas aeruginosa, salmonella, staphylococcus, black mould, E. Coli, streptococcus, and the like, thrive in a cool, damp and dark environment. A bacteria concentration of as little as one to six parts per million can cause illness in humans. Should the case tank become contaminated, the air circulation of the air curtain will repeatedly pass contaminated air over the product until the product on display is thoroughly contaminated. The sanitizing of the case tank of a refrigerated fixture is, therefore, of vital importance. Periodic cleaning by store personnel is inadequate to address the dangers of contamination of refrigerated fixtures by Pseudomonas aeruginosa, salmonella, staphylococcus, black mould, E. Coli, streptococcus, and the like.